[Effects of human cultural neuronal and mesenchymal stem cells on the rat learning and brain state after acute hypoxia].

The aim of the study was to compare the effects of neurotransplantation of cultural neural stem cells (NSC) and mesenchymal stem cells (MSC) on the rat behaviour and brain state after acute hypoxia. It was shown that development of two-way avoidance defensive conditioning in a shuttle box improved in rats-recipients with NSC, but not MSC as compared to control. Both the transplants of NSC and transplants of MSC exert neuroprotective influence on the rat brain. NSC both in vitro (before transplantation) and in vivo (on day 27 after transplantation) gave rise to all neural cell types: stem/progenitor cells, precursors of neurons and glia, neurons and glial cells. MSC population in vitro and in vivo (on day 10 after transplantation) consisted of fibroblast-like cells which were eliminated by day 20 after transplantation and were surrounded by reactive glia. We suggest that effects of NSC may be connected with their good survival and potential to differentiate into neurons and with trophic influence on the brain of recipient, whereas MSC only have possible positive trophic effect at early stages after transplantation.

[Effects of human and rat interferons-alpha on the behavior of rats of different ages. Comparative study of the homology of amino acid sequences].

Effects of chronic intranasal administration of human and rat interferons alpha on feeding and defensive behavior of rats were studied. Natural leukocyte human interferon "Lokferon" (a mixture of alpha interferon subtypes) and recombinant rat interferon alpha of the first subtype were used in the dose of 350 ME per rat daily. In addition, using the databases NCBI and EBI, we quantitatively estimated homology of amino-acid sequences between different subtypes of human and rat interferons. Both human (mostly in young rats) and rat interferons (mostly in old rats) increased rat feeding behavior after food conditioning to an audio tone. In old (but not in young) rats, both human and rat interferons worsened the ability of time interval assessment. In young (but not old) rats, both interferon kinds improved avoidance conditioning. The degree of homology between different human and rat interferons varied from 72% to 77%. Thus, generally, the effects of rat and human alpha interferons (350 ME) on rat conditioning were similar. This may be due to high degree of homology of amino-acid sequences between the two interferons.

[Structural-metabolic changes in neurons of hippocampus and neocortex under the influence of "polydan"].

The aim of this work was to study the influence of different regimens of polydan administration on the structural and metabolic state of neurons of rat hippocampus and neocortex. The animals of experimental groups were administered 75 mg/kg of polydan intraperitoneally once or 5 times. Animals of control groups received similar injections of sodium chloride isotonic solution. Light microscopic study of hippocampus and somatosensory area of neocortex demonstrated 4 types of neurons that could be distinguished according to the degree of their staining with methylene blue. Polydan administration resulted in redistribution of relative proportions of neurons of these types and in increase of the number of nucleoli in these cells, thus indicating an activation of synthetic processes. Quantitative ultrastructural analysis of ribosomes in the cytoplasm of neurons of hippocampal area CA3 and neocortical layer V has confirmed the activation of protein synthesis. Intensification of synthetic processes in neurons was further supported by the analysis of mitochondrial cristae and matrix. It is suggested that synthesis activation in brain neurons is a structural and functional basis for the mnemotropic effect of polydan.

[Effect of polidan on the conditioned memory and structural and metabolic parameters of the rat brain neurons]. / Polidan--vliianie na uslovno-reflektornuiu pamiat' i strukturno-metabolicheskie pokazateli v neironakh mozga krys.

New experimental data on the mnemotropic (nootropic) properties of the well-known drug polidan (a DNA derivative) are summarized. The results obtained by histological techniques showed changes in the brain structure, indicating protein synthesis activation under the action of polidan. These results confirm prognostic function of the concept of evolutionary-molecular basis of memory.